With special 4-pin connector. This is a non-original power supply custom built to work correctly with smaller Alesis products, but NOT for the Quadraverb. (1000ma)
7 foot power cord with a unique connector with 3 circles; plug is 28/32 wide; 1/2" space of outside connectors; similar but will not fit Ampex type. Missing ground pin on socket side. Condition: 8+